Impregnating apparatus



1940- e. PICKFORD ETAL IMPREGNATING APPARATUS 1938 4 Sheets\ wet 1 Filed 001;. 3

I. I I

h l l ual 1940- G. PICKFORD' ETAL IMPREGNATING APPARATUS Filed Oct. 3, 1958 4 Sheets-Sheet 2 &

Nov. 26, 1940.

G. PICKFORD ETAL IMPREGNATING- APPARATUS 4 Sheets-Sheet 3 Filed Oct. 3, I958 NOV. 26, 1940. PICKFORD ETAL 2,222,630

IMPREGNATING APPARATUS Filed Oct. 5, 1938 4 Sheets-Sheet 4' liquid as water.

UNITED STATES PATENT OFFICE,

IIWPREGNATING APPARATUS George Pickford and Bernard S. Lee, Beverly,

Mass, assignors to United Shoe Machinery Corporation, Borough of Flemington, N. .L, a corporation of New Jersey Application October 3, 1938, Serial No. 232,986

49 Claims.

This invention relates to apparatus for impregnating unattached leather soles with a suitable liquidto render them pliant and workable for sole-laying and various other operations that follow.

An object of the invention is to provide improved apparatus for speeding impregnation and for affording automatic operation in which the treatment may be regulated by preliminary adjustments to determine not only its duration but also the number and kind of pressure changesto be brought about in a cycle.

The liquid most commonly used to temper soles is water, and although some shoe manufacturers add one or more other liquids to the water to provide emulsionsaccordingto their preference, it will be convenient forthe purposes of the present description to. refer to the impregnating The apparatus herein illustrated provides for immersing the work in water in a pressure-sustaining receptacle, closing the receptacle to render it pressure-tight after expelling all the free air therefrom by filling it to capacity with water, reducing the pressure of the 'waterin the receptacle below that of the atmosphere (this stage of pressure being hereinafter termed minus 'pressure) maintaining. the minus pressure for a period sufiicient to withthe leather, relieving the hydrostatic tension of the water at the conclusion of a predetermined and regulatable period of time, developing plus pressure (above atmospheric-pressure) of the water, maintaining that stage of pressure for a opening the receptacle, and removing the work therefrom.

The invention further provides for developing a series of stages of minus pressure in alternation with a series of stages of plus pressure, the number of which stages may be varied by preliminary adjustment according to the preference of the user, and the total or aggregate elapsed time of which may also be varied and controlled by preliminary adjustment.

The illustrated apparatus provides for maintaining circulation of the water through the impregnation receptacle during each period of plus pressure, such circulation having the advantage of removing dirt, small particles of leather and other substances while maintaining replenishment of the water in the receptacle. The apparatus includes automatic controls by which the several stages of a cycle may be initiated according to a predetermined sequence without inter vention on the part of the user after a cycle has been starter. The apparatus is so organized and controlled as to remove the treated work from 60. the receptacle and finally to stop the operation draw much if not all the air from the pores of predetermined and regulatable period of time,

level during the intervals of all the moving parts whena cycle has been' completed.

The several features of the invention are herereceptacle and the filling valve, and includes also the mechanism for operating the latter;

Fig. 4 is another diagram of the elements included in Figs. 1 and 2, the conditions differing from those of Fig. 2 in that the output'of the pump is being utilized to develop and maintain plus pressure in the impregnation chamber;

Fig. 5 is an elevation and partial section including automatic hydraulic valve mechanisms by which the pressure of the water in the impregna- I tion chamber may be rendered minus and plus Fig. '7 is an elevation, partly in section, including a manually operable starting lever, the primary valves operable thereby, automatic valveoperating mechanism and a regulatable timing device for controlling the changes of pressure and partly in section, including the receptacle, the closure, the work-carrler, the timing device, and

other units, all the movable elements being represented in their initial positions;

Fig. 9 is a top-plan view of the closure and the mechanism for looking it to the receptacle;

Fig. 10 is an elevation, partly in vertical section, of a float-operated mechanism for supporting an operating weight in its initial position and for releasing it at the conclusion of the filling operation. In this figure the parts occupy their initial positions; v

I Figs. 11 and 12 represent successive positions of certain elements of the mechanism shown in Fig. 10;

Fig. 13 is an elevation, partly in section, indicated by line XIII-XIII in Fig. 10; I

Fig. 14 is a front elevation including the receptacle, a movable guard, and an hydraulic unit for .operating the guard;

Fig. 15 is a vertical section including a detent by which the closure is supported at its highest between cycles of operation;

-Fig. 16 is a vertical section of a double-acting float-operated valve-assemblage for releasing air 'which the hydraulic pump derives its operating power; and

Fig. 18 represents an alternative arrangement I of piping whereby circulation of the water through the impregnation chamber may be elim- .inated without affecting any other condition of operation.

Insome'respects the accompanying drawings are diagrammatic because inan apparatus organized for commercial use many of the elements are so closely related and obscured, one by another, that true pictorial representation thereof would be confusing. For this reason the views that represent thehydraulic circuit and its branches are in the form of diagrams or flat developments in which the individual units are, to some extent, separated merely for the sake of rendering their effective relationships clear. In these views some non-essential details of structure have been omitted in the interest of a clear showing of principles of operation, but relationships and proportions are maintained'as nearly as possible consistently with diagrammatic representation;

An outline of a typical cycle of operations will lay a foundation for subsequent description of individual units, operations and details of apparatus. The work to be impregnated will be placed in an open cage or carrier suspended from the bottom of a vertically movable closure that cooperates with a stationary receptacle to form a pressure-tight impregnation chamber. The closure and the work-carrier are initially raised far enough above the receptacle to facilitate loading the carrier with soles to be treated.

A motor for operating the pump in the hydraulic circuit is initially out of operation, but once the work has been placed in the carrier, the user has only to initiate a cycle by depressing a starting lever against the force of a returning spring.

When this lever is fully depressed, it is caught, by a latch that maintains it in the starting H position until the treating or conditioning period is concluded.

The starting lever operates a detent to release the closure, closes the electrical circuit that operates the pump-motor, and operates a primary valve in the hydraulic circuit, this valve being a quadruple valve according to the construction 5 shown.

the purpose of deflecting the user's hand if it has not already been removed from the path of tha closure. This movement of the guard is completed before the closure can descend far enough to touch the operators hand. When the closure is seated in the mouth of the receptacle. it is immediately locked in pressure-tight relation thereto. If the water initially in the receptacle is not sufllcient to fill the chamber when the closure is seated, a supply of water will flow from the hydraulic circuit into the chamber until the latter is filled, thereby expelling all the free air from the chamber through vents that close auto-- matically when the filling is completed. The supply of water for filling is automatically controlled 7 by a secondary valve that is initially closed but is opened by an element of the mechanism for locking the closure.

The description will proceed on the assumption that the apparatus has been regulated to provide for one stage of minus pressure and one stage of pluspressure of two minutes each. The final stage of the filling operation causesa float to trip a detent by which an operating weight is released. This results in closing a tertiary valve in the filling pipe and at the same time opening a valve in another pipe through which the water from the pump returns at high velocity to a storage tank. This return pipe includes a hydraulic aspirator by which minus pressure is developed in the impregnation chamber and maintained fora measured period of time (c. g., two minutes). When the weight has dropped far enough to initiate this period of minus pressure, its load is sustained by a timing mechanism which is thereupon setin operation by the load, further descent of the weight being retarded by the timing mechanism which has subsequent functions to perform within the time allotted for treatment.

At the conclusion of the period allotted for minus pressure a mechanism that derives its movement from the descending weight, causes a reversal of the two valves last mentioned, one

pumped into this chamber, and when a certain predetermined plus pressure is developed therein, water may flow from the chamber to the storage tank through a return pipe including an adjustable pressure-regulating valve. So long as this condition is maintained, the water in the hydraulic circuit will flow through the impregnation chamber, the pressure-regulating valve, the storage tank and thence to the intake side of the pump to be supplied again to the impregnation chamber. In the meantime, the'weight continues to descend under control of the timing mechanism until it trips the latch that holds the starting lever in itsstarting position.

The primary valve and the starting lever are now returned to their initial positions by a spring,

- thereby diverting the output of the pump from the impregnation chamber to two hydraulic units one of which returns the guard to its initial position and the other of which unlocks the closure and raises it to its initial position. The primary valve also releases the positive pressure in the impregnation chamber. The return of the starting lever to its initial position also opens the electrical starting switch by which the operation of the pump-motor was initiated, but at this stage, the motor is maintained in operation by a supplemental switch in a branch of the motor circuit. As the closure is elevated by its hydraulic unit, it picks up and carries the weight that operates the timing mechanism and other parts of the apparatus, and the weight returns the timing mechanism to its initial position. When the closure has risen to its initial level, it opens the I supplemental switch in the stopping branch of the motor circuit. All flow in the hydraulic means until the starting lever lisoperated to initiate the next cycle.

When the operating weight reaches its highest level, it is caught by another detent that supports it individually until the closure is locked to the impregnation receptacle in the next cycle. This detent is the one hereinbefore mentioned that is tripped by a float at the conclusion of the opera tion of filling the impregnation chamber to full r capacity prior to development of minus pressure therein. I

The general organization'of the illustrated apparatus is similar in some respects to that illustrated and described in United States Letters Patent No. 2,114,999, granted April 26, 1938, on application. of Fickett, Forman, and Arthur, the

similarities being hereinafter pointed out, but 7 whereas the apparatus illustrated herein has proclosure are arranged to slide up and down on,

guide-rods 23 afiixed to the receptacle and connected above the latter by a stationary cross-head 24 that supports a hydraulic cylinder 25. A foraminous cage I9 is aflixed to the under side of the closure to receive the work to be impregnated and to carry the work into and out of the impregnation chamber. The closure is depressed and raised once in each cycle by a piston 26 (Fig. 4) in the cylinder 25, the piston and the closure being connected by a rod 21 not affixed to the closure but connected'thereto through the medium of locking mechanism represented in Fig. 9 and to some extent in Fig. 3.

The locking mechanism comprises a cylindrical toothed rack 28 aflixed to the lower. end'of the 40 piston-rod 21, and intermeshed with four pinions 29 mounted on the cover, and engaging respectively rack-teeth formed on four radial looking bars 30 (Fig. 3). These bars-are arranged to slide out andin on the upper surface of the 45 closure 2| When the closure is supported by the piston-rod, the weight of the closure retracts the locking bars 30 against stops 3| as shown in Fig. 9, the outer ends of the bars being then flush with the rim of the closure which may descend 50 into the mouth of the receptacle 20 to-be seated upon a rubber gasket 32 (Fig. 8) surrounding the mouth of the chamber. A slight additional down-- ward movement of the piston-rod after. the closure is, arrested by the gasket causes the cylin- 55 drical rack 28 to turn the pinions 29 and thereby project the locking bars 30 under an internal flange 33. This flange and the locking bars cooperate not only to lock the closure to tlie receptacle but also to produce a .wedging efiect by I 60 which the closure 'is forced with increased pressure against the gasket. When the piston-rod is raised, it first retracts the locking bars 30 to unlock and release the closure and thereafter raises the latter. This mechanism for operating the closure and the locking members is virtually the ported at its highest level by a detent arranged to be tripped manually when a cycle of operations is initiated. Thedetent for this purpose is shown in Fig. 15 and comprises a member 34 supported 75 by the cross-head 24 and arranged to be engaged by a vertical flange 35 of one of the brackets22.

' The detent is mounted on a horizontal pivot-pin 36 and is provided with two cooperative gripping portions 31 arranged to'be engaged by opposite faces of the flange 35. A. light tension spring "exerts a pull against the detent in a direction to cause a gripping action of the portion. 31 when the flange 35 is between them, and this gripping efiect is augmented by the load tnu's supported. The flange 35 may rise between the .portions 31 without encountering any appreciable resistance therefrom .but once the gripping relation is established, the flange 35 cannot be released except by rocking the detent in a direction counterto that induced by the spring 38.

' A tripping rod 39 connects the detent 34 with a manually movable starting lever 40 (Fig. 7). The upper end of this rod is bent to form a hook and the hook is loosely engaged with a stud aflixed to the detent, the connection affording a slight range of lost motion to insure gripping action of the detent under the influence of the spring 38. The starting lever'40 is aflixed to a rock-shaft 4| and is mounted adjacent to the mouth of the receptacle 20, preferably at the right of the receptacle; When the handle portion of the starting lever is depressed (Fig. 7), a projection 42 formed on the lever near its rear end is caught by a pivoted latch 43, and the lever is thereby maintained in the starting position until the latch is automatically tripped at the conclusion of an impregnating period of predetermined and regulatable duration. A compression spring 44 normally raises the rear end of the latch tothereto for depressing the rear end of the latch.

a weight 48 arranged to slide on the rod 46, and a collar 49 affixed to the rod below the weight for receiving the load of the'weight at an intermediate stage of the cycle. The descent of the rod, when thus loaded. is retarded by a regulatable timing device 50 represented as a hydraulic dash-pot but it has no hydraulic communication with the other hydraulic circuit;

hereinafter described. This hydraulic timing device is, to all intents and purposes, similar to the corresponding timing. device shown and described in the above-mentioned patent, but the, details for regulating its timing effect are other wise arranged.

The upper and lower ends of the dash-pot cylinder are connected by a hydraulic transfer vpipe 5| in which a'check-valve 52 is interposed to prevent upward flow except that afforded by a bypass 53 which includes an adjustable needlevalve 54. The restriction due to this valve 54 controls the speed of descent of the piston in the dash-pot cylinder, butwhen the piston rises during the last stage of a cycle of operations, the check-valve 52 permits rapid transfer of the liquid from the upper end of the cylinder to the lower end thereof. The stem of the needle-valve is provided with a cylindrical hand-wheel having Y a scale of marks which cooperate with a stationary index-pointer 55 for regulating purposes.

The weight 48 is elevated to its highest level When the weight is being raised by this 46. The space between the collars 49 and 51 is greater than the depth of the weight to provide a range of relative movement between the weight and the rod for a' purpose hereinafter explained. The range of this relative movement may be altered by securing the collar 49 to the rod. at various levels for purposes of regulation, three different predetermined positions of adjustment being provided by a series of small depressions formed in the rod to receive the point of the set-screw in the collar. In Fig. 7, the setscrew is engaged with the lowest of these three depressions but two of them are exposed to view and indicated at 58.

When the closure 2| descends at the beginning of a cycle of operations, the weight 48 does not descend with it but remains caught at its highest level until shortly after the closure is,

locked to the receptacle. For this purpose a bar 59 is affixed to the weight (Fig. 8) and projects upwardly therefrom. The upper end of this bar (Fig. 10) is formed to extend between two cooperative jaws 60, 60 that project laterally from a lever iii to grip the bar and provide a detent. A horizontal pivot-pin 62 connects this detent with a stationary supporting bar 63. Because of the location of the pivotpin 62, the weight of the detent causes the jaws normally to grip the bar 59 and. the gripping effect is amplified by the load of the weight 48, but to insure a positive supporting eiiect, a shallow depression is formed in one face of the bar 59 to receive the upper jaw 68 and to provide a narrow ledge or shoulder to overlie the latter. A slight upward movement of the free end of the lever BI is sufficient to release the bar 59, and a slight force is suflicient to produce such movement.

Tripping movement of the lever BI is caused by a mechanism comprising a tension spring 64, a rocker 65, and a link 88. This link is shown in Fig. 13 as a loop oi wire through which the free end of the lever 8i extends loosely. The link is suspended from a pivot-pin 61 projecting from one end of the rocker, 65. At a point midway between its ends, the rocker is mounted on a supporting pivot 68 that may be secured to any convenient fixture such as a bracket 69. The opposite end of the rocker carries a laterally projecting pin 18 to which one end of the operating spring 64 is hooked. The other end of this spring is hooked through a small hole I2 bored in a trigger H. The spring is always extended and is effective to operate the rocker 65 but its operation is'controlled by the trigger II A finger 13 formed on the trigger projects under one end of the rocker to raise that end initially to the position shown in Figs. 10 and 11. Another portion of thetrigger overlies a vertically movable valve-stem 14 to which a float I5 is secured. Between its ends the trigger is mounted on a supporting pivot I6.

When the parts are in their initial positions, as shown in Fig. 10, the line of force exerted by the spring 64 is slightly above the axis of the pivot-member 68. This "line is represented by broken lines A-A in Figs. 10, 11, and '12 and in each instance it intersects the points 19 and 12. The spring is therefore effective to maintain the rocker 65 initially against a stop I69 (Fig. 10), but when the trigger is tilted to the position represented in Fig. 11, as by upward movement of the float, it carries the line of force A--A below ,the axis of the pivot-member 68, whereupon the spring becomes effective to tilt the rocker to the fills the pipe 18 and partially fills the bowl 'II to operate the float. Air initially in the pipe I8 may escape through a port 19 in the bowl and thence around the upper end of the valve-stem 14, but when the float is raised by water in the bowl, it not only operates the trigger H but also closes the port 19 by carrying a valve-member 89 to a seat at the lower end of this port. This valve is effective to maintain plus pressure of the liquid in the receptacle 20, but the valve-stem 14 also carries a valve 81 arranged to engage a seat at the upper end of the part I9 to maintain minus pressure of the liquid in the receptacle.

One other result of moving the starting lever 49 to'its starting position as shown in Fig. 7 is to close an electrical circuit for operating an electric motor 82 represented conventionally in Fig. 17. The purpose of this motor is to operate apump 83 (Figs. 1, 2, and 4) by which water is forced through a hydraulic circuit to be utilized not only for impregnating the work but also for operating various units to be described.- When the rockshaft 4| is turned by depressing the.handle of the starting lever, it closes a starting switch 84 that is initially maintained in open position by the spring 45, if not by an individual spring.

As shown in Fig. 17, the motor 82 and the starting switch 84 are in series in a circuit that derives current from a supply circuit 85. A knife switch 86 may be provided to connect the motor-circuit with the supply circuit. The motor- ,circuit also includes a branch in which a stopping switch 81 is interposed to maintain the motor in operation after the starting switch 84 is opened. The switch 81 is effective only during the final stage of a cycle while the closure 2| is rising from the receptacle 28 to its initial position, at which time the starting switch 84 is open, but when the closure reaches its highest level, the stopping switch 81 is opened automatically .to terminate the cycle. For this purpose the switch 81 is secured to the under side of the crosshead 24 (Fig. 8) to be opened by one of the guiding brackets 22 in opposition to 'a closing spring (not shown). The switches 84 and 81 may both be limit switches of well-known commercial construction. With the circuit thus controlled, the motor 82 will receive operating current when either of the switches 84 and 81 is closed and will be deprived of current only when both are open.

The hydraulic operating circuit including various branches is represented diagrammatically in Figs. 1, 2, 4, and 5. In Figs. 1, 2, and 4, certain units and operating connections are represented in continuous lines and others are represented in dotted or broken lines, the significance of the dotted lines being that no water flows in the elements so represented at the respective stages of the cycle with which these views are concerned. I

The pump 83 is supplied with water from a storage tank 88 through a pipe 89 and the output of the pump is forced with considerable pressure through a pipe 9| to a primary controlling valve indicated as a'whole at 99. This valve comprises four individual chambers 92, 93, 94, and

through which the water may flow under the 75 control of valve members 98, 91, and 98 carried by two vertically movable stems 99., The valve members stand initially in the positions shown in Fig. 1 but they are all depressed simultaneously a to the positions represented in Fig. 2 by depressing the handle of the starting lever 40 as hereinbefore described, The operating connection between the-starting lever and the valve-stems includes an equalizing bar or block I and a pair ofconnectinglinks such as that indicated at IOI (Fig. '7). The equalizing bar is not rigidly fastened to the valve-stems but has some capacity for rocking to equalize the pressure of the valvemembers against their seats. This connection provides not only for depressing the valve stems butalso for lifting them.

Once the pump83 is set in operation with the primary valve-members depressed as in Fig. 2,

the output 01' the pump flows through pipe 9|,

' chamber 92, chamber 93, pipe I02, and branch pipes I03 and I04. The pipe I02 hereinafter termed a filling pipe is connected to the receptacle 20 to supply water to the impregnation chamber therein, but between the branch I 04'and the receptacle, this pipe is provided with a secondary valve I and a tertiary valve I08. The valve I08 is initially open but the valve I05 is initially closed. Consequently, the first result of supplying water under pressure to'the pipe I02 isto distribute the supply only to the branch pipes' I03 and I04. The pipe I03 conducts some of the Water into the lower end of a small hydraulic cylinder I01 while the pipe I04 conducts some of it into the upper end o f.the cylinder 25. Pipes I08 and I 09 provide for returning water from the upper end of the cylinder I01 and from the lower end of cylinder 25 into the valve chamber 94 from which it flows into the chamber 95 and thence through a return pipe 0 to the storage 40 tank 88. No part of the latter pipe is above the level of. the chamber 95, and the water is therefore drained by the force of gravity from the chamber 95 into the storage tank.

A check-valve III in the pipe I09 has a con- 45 struction that permits restricted fiow'from the lower end of the cylinder. 25 to the chamber 94 and, at a later stage in the cycle, permits unrestricted flow in the opposite direction. The purpose of this check-valve is-to retard the descent of the closure 2| and thereby accelerate the elevation of a guard I I2 carried by the piston II 3 in the cylinder I01. I As shown in Fig 14. which is a front elevation, the guard I I2 extends across the front of he receptacle 20 and its upper edge is initially elow the mouth of the receptacle, but when the guard is raised it will deflect the operator's hand from the mouth of the receptacle and thus give warning that the closure is about to descend. It (30 will also prevent thrusting ones hand between the mouth of the receptacle and the closure when the latter is nearing the receptacle, thus counteracting any impulseto rearrange the soles previately locked to the receptacle as hereinbefore includes an adjustable pressure-regulating valve- ||1 by which the pressure in the pipe 9| may be restricted to any desired limit. I

Referring to Fig. 3, one of the locking bars 30 carries a member II8 the purpose of which is to open the secondary valve (filling valve) I05 incidentally to locking the closure. This valve is preferably of the gate type and is initially closed, as shown in this figure, to prevent flow of water into the. receptacle 20 prior to locking the closure. An arm I I9 aillxed to the stem of this valve is engaged by a fork at one end of an operating lever I20 that is normally maintained-in closing position by a compression spring I2I. The upper endof the operating lever extends above the fulcrum pin |22 on which the lever 'is mounted, and when the closure is seated, the member 8 and the operating lever are cooperatively related as shown in this figure. Consequently, when the locking mechanism is operated, the member II8 opens the valve I05 to admit water fromthe pipe I 02 into the receptacle.

Even though considerable water remains in the receptacle 20 .at theconclusion of each cycle it is necessary to supply some additional water in the next cycle to fill the impregnation chamber and operate thefloat 15 (Fig. 10).. This requirement is satisfied by the above-described ope'ration of the filling valv I05. As the filling progresses the water expels air from the impregnation chamber first through an automatic doubleaoting venting valve I23 screwed into a tapped hole in the closure 2| (Figs. 9 and 16) The casing of this. valve is in the form of a cup and contains a float I24 from which a valve-stem I25 extends downwardly through a venting port I28. The valve-stem carries two valve members I21 and I28 arranged respectively below and above the venting port. The valve member I28 is normally seated as shown in Fig. 16, and in this position it is effective to maintain minus pressure second earlier than the float shown in Fig, 10' be-' cause the latter is at a higher level.-

An earlier part of this description concerning the mechanism included in Fig. 10 explains how the weight 48 is released from the'member 6| when the float 15 rises. At that instant the 111% 58 does not stand at the level shown in Fig. '1 because it has already been carried nearly to the mouth of the receptacle 20 by the descent of the closure. Consequently, when the weight 48 is released as a result of filling the impregnation chamber with water, the weight drops immediately to the collar 49 by which it is momentarily arrested and thereafter permitted to descend slowly to depress the rod 48. As hereinbefore stated-this description of a cycle of operations is predicated upon the assumption that the various hydraulic c0ntrols are adjusted to sub- 3 0 the work in the impregnation chamber to one two-minute stage of minus pressure and one two-minute stage of plus pressure. Accordingly, the needle-valve 54 is adjusted to require four minutes for the descent of the rod 45 from the instant when the weight 48 is tripped until the collar 41 trips the latch 43 to release the starting lever 40.

The mechanism at the upper right of Fig. '7 is instrumental in bringing about successive stages of minus pressure and plus pressure in the impregnation chamber. This mechanism comprises a toothed quadrant I30, a lever I3I, a link I32 connecting them, and a link I33 connecting the lever I3I and the weight 48. The quadrant is arranged to be oscillated about a fixed axis provided by a fulcrum .pin I34, and the lever I3I is arranged to be oscillated about another fixed axis provided by a fulcrum pin I35, both of these fulcrum pins being supported by a fixture I35. The lever I3I is provided with an arcuate groove or slot I31 in which a clamping stud forming a pivotal connection with the link I32 may be adjusted toward and from the axis of the fulcrum pin I35, this stud having a hand-nut I38 by which to secure the desired setting. The radius of the curvature of the slot or groove I31 is commensurate with the effective length of the link I32, and the parts are so organized that when they stand in their initial positions as shown in Fig. '1, this curved slot or groove is concentric with respect to the pivot-pin by which the upper mediate point in-the pipe 5| to the storage tank. 88, but since this valve is initially clos d no t r 1 end of the link I32 and the quadrant I are connected. The total range of vertical movement of the weight 48 is the same under all conditions of regulation but its gnovement is communicated to the quadrant in various ratios according to the setting of the link I32 except when the hand-nut I38 is set at the neutral position in coaxial relation to the fulcrum pin I35.

The gear-teeth formed on the quadrant I30 engage a pinion I to impart rotation thereto. This pinion is affixed to a shaft I4I (Fig. 6) which also carries means for rotating a wristpin I42 in one direction only, indicated by an arrow.

The driving mechanism carried by the shaft l4I comprises an arm I43, a pawl I44 carried thereby and a leaf-spring I45 by which the pawl is normally maintained, in a position to abut and drive the wrist-pin, but the leaf-spring I45 permits the pawl to click over the wrist-pin when the shaft rotates reversely. The pawl and the arm I43 are connected by apivot-pin. The wristpin I42 is aflixed to a disk I45 and projects to one side of the disk for connection with a member. I41 and from the opposite side of the disk for co-operation with the driving pawl. The disk I45 is mounted on the shaft I4I but is not driven thereby except as it may be driven in one direction by the pawl. The function of this mechanism is to operate a pilot valve I (Fig. 5) by which water is supplied from the pipe 9| by wayof the pipe I5I to a hydraulic cylinder I5I. The piston I52 in this cylinder operates the tertiary valve I05 and a similar valve I53 both at the same time to develop minus pressure and plus pressure alternately in the impregnation chamber 20. Fig. 5 represents the valves I05 and I53 in their initial positions, the .valve .I05 being open and the valve I53 being closed. The valve I53 is interposed in a pipe I54 through which water may flow at high velocity from an intercan flow through it while the impregnation =chamber is being filled.

'On the other hand, the initial drop of the weight 48- brought about by filling the impregnation chamber produces a rapid initial movement of the quadrant I30 (Fig. '1), and the range of this initial movement is suillcient to turn the pinion I40 through about 180 of one revolution, thereby producing a rapid hydraulic operation which closes the valve I05 and at the same time opens the valve I53. Now, the output of the pump 83, being no longer required for any other purpose, flows through the pipe I54 and through a hydraulic aspirator I55 interposed therein. .The suction pipe I55 is in communication with the impregnation chamber and is provided with a check-valve I51 that has no effect when the aspirator is in operation but prevents water from flowing into that chamber from the aspirator at other times. So long as the valves I05 and I53 remain in the position last described the water flowing through the aspirator I55 will maintain a powerful minus pressure in the impregnation chamber to withdraw air from the pores of the soles therein.

Continuing the description of the mechanism for operating the valves I05 and I53, the stems of these valves are provided with operating arms 'I58 and these arms are coupled by'a link I59 that causes one valve to open when the other closes, and vice versa. The operating connection between-the piston I52 and these coupled valves preferably includes a resilient member such as a moderately'stiif helical spring I50 both ends of which are secured to fittings to insure a pulling action as well as a pushing action. This spring counteracts the curvilinear component of a the operating arm to which it is connected and insures tight closing of first one valve and then the other. accordingly, the range of travel of the piston I52 is in excess of that required by the valves, but the surplus motion of the piston is expended in distending and compressing the spring alternately.

,The water for operating the piston I52 flows from the output side of the pump 53 through a small pipe I5I by which it is conducted into a chamber I52 in the pilot valve I50. The stem I53 of the pilot valve is provided with two slide valves I54 and I55 both aiiixed thereto and arranged to remain respectively above and below the inlet port to which the pipe I5I delivers the water. When the slide valves are in their initial positions as shown in Fig. 5, the hydraulic pressure is communicated to the lower end of the cylinder I 5| by" the chamber I52 and a connecting pipe I55, but when the valve-stem I53 is raised to the upper limitof its travel, the slide valve I55 -closes communication between the supply pipe I5I and the pipe I55 and opens communication between the latter and a return pipe I51. -At the same time the slide valve I54 rises above a connecting pipe I58, thereby opening communication between the supply pipe I5I and the upper end of the cylinder Ill. The operating liquid is thus caused to depress the piston I52, the water expelled thereby from the lower end of the cylinder being caused'to flow through pipe I55, chamber I52, and return pipe I51 which conducts it into the return pipe IIO (Fig. 4). In

like manner, when the piston I52 is rising to its initial position the water thereby expelled from the upper end of the cylinder I5I flows through the pipe I68, the chamber .I62, and thence through a branch of the return pipe I61.

The valve-stem I63 receives its motions from the wrist-pin I42 to which it is connected by a link preferably made in two parts that are relatively adjustable to regulate its 'efiective length within close limits and thereby vary inversely the length of time allotted to minus pressure in the impregnation chamber and the length of time allotted to plus pressure. By shortening the effective length of the link the range of travel ofthe slide'valves I64 and I65 will be raised vwith respect to the casing of the pilotvalve and will thereby retard'or postpone the termination of the minus stages and the beginning of the plus stages. The minus stages will be correspondingly prolonged and the plus stages will be correspondingly shortened, but to prolong the plus stages and shorten the minus stages it is only necessary to increase the effective length of the link. The lower section of the link is a cylindric rod I10 having a right-angular bend at its lower endto provide a pivotal connection with the valve-stem I63. The upper end of this rod is provided with a screw-thread, and is arranged to slide in holes bored in spaced confronting lugs formed on the member I41. The

space between these lugs is occupied by an ad- I40 are retarded by the needle-valve 54, and at the conclusion of a two-minute period of minus pressure'in the impregnation chamber, the slide members I64 and I65 in the pilot valve will have returned to their initial positions as shown in 4Q Fig. 5 and will thereby cause the piston I52 to close the valve I53 and open the valve- I06. This will restore the conditions of flow and pressure represented in Fig. 2,,and water being pumped through the pipe 9| will no longer flow through 45 the aspirator I55 but will flow through valve chambers 92 and 93, pipe I02, valves I06 and I05, thence through the impregnation chamber 2 and back to the storage tank 88 through a return pipe I13 which would be represented in solid lines were it not for the fact that this figure is primarily intended to represent conditions established at an earlier stage in the cycle (fillingstage) ,in which thereturn pipe I13 had no duty. This return pipe is provided with a pressure-regulating valve I14 capable of being adjusted to require any desired pressure to force the water through it. Consequently, the pressure thus developed by the pump and the valve I 14 is maintained in the impregnation chamber during the remainder of the time allotted for treatment of the work, andat the same time the water continuesto flow through the chamber at the established positive pressure. Preferably the pressure-regulating valve I I1 will be adjusted for a pressure above that for whichthe valve I14 is adjusted, to insure pressure in the impregnation chamber for which the valve I14'is adjusted.

Ultimately, the collar 41 (Fig. '7) on the rod 46 trips the latch 43 to release the starting lever 40, whereupon the tension spring 45 returns the starting lever to its initial position. Both valvestems 99 are thereby raised to their initial positions (Fig. 1) and the output of the pump 83 now flows from pipe 9I through chambers 92 and 94 through pipes I03 and I02 into the chamber'93 and thence to the return pipe IIO. Also, as the piston 26 rises, the water above it is expelled through pipes I04 and I02 and thence'through the chambers 93 and 95,to the return pipe IIO.

As the locking member shown in Fig. 3 is retracted to release the closure it also releases the operating lever I 20,'whereupon the spring I2I operates to close the filling valve I 05, but between the instant of relieving the pressure in the impregnation chamber and that of closing the valve I05 the water in the stand-pipe 18 and the bowl 11 (Fig. 2) returns to the receptacle 20 and expels a corresponding quantity through the valve I05 and the. pipe I02.

Although the return of the starting lever 40 to its initial position opens the starting switch 84 (Fig. 17) in the electrical circuit, the motor 82 and the pump continue in operation because the stopping switch 81 remains closed while the clossure is rising and is not opened until its operating arm I15 (Fig. .8) is raised by a portion of theguiding bracket 22 shown at the left of that fi ure. When the switch 81 is opened, the detent 34 (Fig. 15) becomes effective to grip the flange 35 for the purpose of supporting the closure in its elevated position./

As the closure 2I rises, the, lug 56 that projects laterally from the guiding bracket 22 at the right of Fig. 8 picks up the operating weight 48, the weight in turn picking up the collar 51 on the rod 46.. The weight and the rod are thus returned to, their initial positions and the weight is lever 6I (Fig. 10)

In the final stageof upward movement of the closure the trigger 1I1 (Fig.v 10) is returned to its initial position by a light rod I16 suspended therefrom,the upper end of this rod having an eye. that surrounds a lug I11 projecting from the triggers The rod I16 extends loosely through a guiding fixture I18 (Fig. 15) and its lower end is-arranged to be engaged by a striker I19 carried by the adjacent guiding bracket 22. To insure resetting the trigger without damaging any of the parts, some member of this mechanism should be capable of yielding, and for this reason the striker I19 is represented as a leaf-spring capable of being deflected while resetting the trigger. As the trigger returns to its initial position from that represented in Fig. 12, the lug 13 projecting therefrom restores the rocker to its initial position, thereby raising the pin 10.

At the. same time the hole 12 in the trigger rises member 60 to maintain the parts in readiness for the next tripping operation. I

Referring to Figs. 5, 6, and 7, since one complete revolution of the wrist-pin I42 is required for each complete cycle of pressure oscillation in the impregnation chamber. and since the mechanism shown at the upper right of Fig. 7 is capable of'being regulated to produce one, two, or three cycles of pressure oscillation at the option o! the user. the method of procedure to vary the number of such oscillations is as follows: Assuming that three cycles of pressure oscillation are desired, the user will loosen the hand-nut I38 and shift it away from the fulcrum member I35 to the remote end of the groove or slot I31 where he will tighten it to preserve the adjustment. This will increase the range of movement imparted to the quadrant I30 by the weight 48 which has constant limits of vertical movement. The maximum movement of which the quadrant I30 is capable under these conditions is suflicient to impart three complete revolutions to the wristpin I42 instead of only one complete revolution as when the link I32 is adjusted as shown in this figure.

Now, when the link I32 is set to impart the maximum length of movement to the quadrant a relatively short initial drop of the weight 48 will be suificient to terminate the filling operation and initiate the first stage of minus pressure which, under all conditions of regulation, are brought about by the first semi-revolution of. the disk I48. Therefore, to coordinate the length of the initial drop of the weight and the setting of the link I32 for a series of three cycles of pressure oscillation, the load-sustaining collar 49 on the rod 46 should be raised to place the set-screw of that collar in register with the highest depression 58. For a series of two cycles of pressure oscillation the collar 49 will be located in register with the intermediate depression 58 and the link I32 will be located in register with an intermediate notch I80 formed in the lever I3I to receive a .boss on the nut I38. If plus pressure alone is desired, in the impregnation chamber without any stage of minus pressure it is only necessary to shift the connecting link I32 to the position where the nut I38 will be in coaxial relation to the fulcrum pin I35. With such an adjustment the quadrant I30 will remain stationary while the weight 48 and the lever I3I execute their regular movements, but this will not deprive the latch 43 of the tripping effect of the weight under the control of the dash-pot 58.

When the controlling mechanism is adjusted for plus pressure alone, such pressure will be developed in the impregnation chamber .at the conclusion of the filling operation (Fig. 2) and the water will continue to be pumped into and throughthe chamber and will return to the storage tank 88. through the pressure-regulating valve I14 until the starting lever is tripped as hereinbefore described.

The alternative arrangement of piping represented in Fig. 18 may be used if it is desired to eliminate circulation of the water through the impregnation chamber during the periods of plus pressure therein. According to this diagram, the supply pipe I82 and-the return pipe I13 are connected directly one with the other to return the circulated water to the storage tank 88 without flowing it through the receptacle 28, but a short pipe I12 leading from the pipe I82 to the impre'gnationchamber provides a connection for filling the chamber and for developing plus pressure therein. Circulation through the impregnation chamber maybe otherwise eliminated without providing this alternative arrangement of piping, as by adJusting the pressure-regulating valve I14 to require a greater opening pressure than the valve I I1.

As shown in Fig. 8, the receptacle 28 is provided with-a duct I48 the mouth of which is above the "aaaaeso level of the gasket 32 but below the upper end of the receptacle. If any water overflows the gasket it will flow at atmospheric pressure into this duct and thence through a return pipe I49 i and into the storage tank 88.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of theUnited States is:

, 1. A hydraulic apparatus comprising means arranged to form a pressure-sustaining impregnation .chamber, means arranged to supply an impregnating liquid under a head of pressure to said chamber, a valve arranged to close communication between said chamber and the source of said liquid, hydraulic means arranged to produce minus pressure of the liquid in said chamber when said valve is closed, and a valve arranged to control the operation of said hydraulic means.

2. A hydraulic apparatus as defined in claim 1 in which the liquid for operating said hydraulic means and the liquid for supplying said chamber are both derived from a common source.

3. A'hydraulic apparatus as defined in claim l in which said valves are operatively coupled by means arranged to impart opening movement to one when the other closes, and vice versa.

4. A hydraulic apparatus as defined in claim 1 in which a power-operated mechanism is arranged toclose one of said valves and open the other, and vice versa.

5. A hydraulic apparatus as defined in claim -1 in which said supply means, said impregnation chamber and a return conduit are organized to form an endless hydraulic circuit and to circulate the liquid through said impregnation chamber when said valves are set to develop plus pressure therein.

6. A hydraulic apparatus as defined in claim 1 in which said supply means, said hydraulic means and a return conduit are organized to form an endless hydraulic circuit.

'7. A hydraulic apparatus as defined in claim 1 in which said supply means, said impregnation chamber and a return conduit are organized to form an endless hydraulic circuit and in which said hydraulic means is arranged to form a bypass in said circuit around said chamber.

8. A hydraulic apparatus comprising a.receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, means for supplying an impregnating liquid above atmospheric pressure to said chamber, and automatic hydraulic means responsive to the pressure of said liquid to produce successive stages of minus and plus pressure of the liquid in said chamber.

9. A hydraulic apparatus as defined in claim 8 in which said automatic means are regulatable to vary the durations of said stages of minus and plus pressure.

10. A hydraulic apparatus as defined in claim 8 in which said automatic means utilize liquid from said supply means to produce said stages of minus'and plus pressure in the impregnation chamber.

11. A hydraulic apparatusas defined in claim 8 in which said automatic means include an adjustable mechanism capable of regulating the stages of minus pressure and those of plus pressure of the liquid in said chamber by inversely varying their durations.

12. A hydraulic apparatus as defined in claim aa'aaeso- 8 in which said automatic means include a regulatable control by which to vary the number of stages of minus pressure and plus pressure of the liquid in said impregnation chamber in an allotted period of time.

13. A hydraulic apparatus comprising a receptacle anda removable closure designed to form a pressure-sustaining impregnation chamber,

means for supplying an impregnating liquid above atmospheric pressure to said chamber, a timing device, automatic means controlled by said timing device to retract said closure at the conclusion 0L9. measured time interval, and automatic means also controlled by said timing device to produce alternate stages of plus pressure and minus pressure of the liquid in said impregnation chamber during said time interval.

14. A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, means including a valve'for supplying an impregnating liquid above atmospheric pressure to said chamber, a hydraulic aspirator arranged to produce minus pressure of the liquid. in said chamber when said valve is closed, and a valve arranged to control the flow of operating liquid through said aspirator.

15. A hydraulic apparatus as defined in claim 14 inwhichsaid means for supplying liquid to saidchamber also supplies the operating liquid to said aspirator.

16. A hydraulic apparatus as defined in claim 14 in which automatic mechanism operates said valves. in timed relation; one to the other, to produce successive stages of minus and plus pressure of .the liquid in said chamber. I

17. A hydraulic apparatus as defined in clai 14 in which a hydraulic unit is arranged to retract said closure. from the receptacle, a valve'is arranged to admit liquid from said supplying means to said unit, and automatic mechanism is' arranged to operate said valves in a predetermined sequence to produce successive stages of minus pressure and .plus pressure of the liquid.

.in'said chamber and'thereafter to initiate the retracting operation of said hydraulic unit.

18. A hydraulic apparatus comprising means to provide a pressure-sustaining impregnation chamber, means including a valve for supplying. an impregnating liquid under a head of pressure to saidchamber, and means controlled'by the rise of liquid in said chamberto close said valve from said pumping means throughalternative conduits to produce minus pressure and sure alternately in saidchamber;

20. A hydraulic apparatus as defined in claim 19 in which said automatic controlling means include regulatable timing mechanism arrangedto regulate and control the durations of the inplus presdividual stages of .minus pressure and plus presdurations of the stages ofminus pressure and plus pressure in said chamber may 'be varied inversely.

22. A hydraulic apparatus as defined in cl im 19 in which said automatic controlling means cludevhydraulic means operable by liquid from saidpumping means to effect the alternate stages of minus and plus. pressure in said chamber.

, -23. A hydraulic apparatus as defined in "claim' 19 in which said automatic controlling means include regulatable mechanism by which the numberof stages of minus pressure and stages of plus pressure in said chamber in an allotted period of time may be regulated.

24. In a. hydraulic apparatus of the type in which poweroperated mechanism is arranged to raise a'closure from its cooperative relationship with a pressure-sustaining receptacle in which work is to be'impregnated andjnto which an impregnating liquid is to be admitted under pressure from a source of supply; means arranged to control the admission of liquid from said source, hy-

' draulic means arranged to develop minus pressure of the liquid in said receptacle, a timing mechanism, means governed by said timing mechanism to arrestthe admission of liquid into said receptacle and start the operation of said hydraulic minus-pressure means, and means also governed by said timing mechanism to relieve abnormal pressure of the liquid in said receptacle at the conclusion of a predetermined time interval and initiate the operation of said closure-raising means.

25. In a hydraulic apparatus of the type in which a pressure-sustaining chamber for work to minus pressure and plus pressure ofthe liquid in said chamber, said automatic means including a timing mechanism by which the time alloted to said pressure stages is governed and by which the operation of said closure-retracting means is initiated at the conclusion thereof.

26. In a hydraulic apparatus of the typein which impregnating liquid is supplied with plus pressure from a source of supply to a pressuresustaining impregnation chamber; a hydraulic aspirator 'in' communication with said chamber and with said source of supply to develop minus pressure in the chamber, valve-operating mechanismand cooperating valves operable thereby to control the admission of liquid from said source to said chamberand to control-the operation of said aspirator, and a timing mechanism by which said valve-operating mechanism is controlled to effect a series of stages of minus pressure and plus pressure alternately of the liquid in said chamberin an allotted period of time, said valve-operating mechanism being regulatable to produce one or more stages of minus pressure and one or more stages of plus pressure in each period allotted by said timing mechanism.

27. -A hydraulic apparatus comprising means arranged to form a pressure-sustaining impregnation chamber,- a hydraulic aspiratorin communication therewith,a so ce' of plus hydraulic pressure having a supply branch in communica-j 7 5 tion with said chamber to develop plus pressure therein and a branch including said aspirator to develop minus pressure in said chamber, coupled valves insaid branches respectively to close one a when the other is open, and vice versa and a check -valve arranged to prevent flow from said 'aspirator into said chamber.

28. A hydraulic apparatus comprising an endless hydraulic circuit including a pump and a plurality of branches for returning liquid from the output side of said pump to the intake side thereoij, one of said branches including a pressure-regulating valve and a pressure-sustaining work-receiving chamber through which the liquid must flow before reaching said valve, another one of said branches forming a by-pass around said chamber and said valve and including an aspirator in communication with said chamber, and valve means arranged to direct the liquid through said branches alternatively to develop minus pressure, on the one hand, and plus pressure, on the other, in said chamber.

29. A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnationchamber,means including a valve to supply an impregnating liquid above atmospheric pressure to said chamber, means operable automatically to open said valve, hydraulic means arranged to' produce successive stages of minus pressure and plus pressure of the liquid in said chamber, hydraulic means arranged to retract said closure from the receptacle, means arranged to arrest the supply of impregnating liquid to said chamber and supply the liquid to operate said rectracting means, and automatic mechanism including a timing unit arranged to control the durations of said pressure-stages and initiate the operation of said retracting means.

30. A hydraulic apparatus comprising a recep- 40 tacle and a removable closure designed to form a pressure-sustaining impregnationchamber,means arranged to supply an impregnating liquid above atmospheric pressure to said chamber, hydraulic means arranged to produce minus pressure of the liquid in said chamber, automatic means arranged to control the liquid to effect successive stages of minus and plus pressure of the liquid in said chamber, and means controlled by said controlling means to arrest the supply of liquid to said chamber and retract said closure from the receptacle" 31. A hydraulic apparatus comprising a receptacle and a removable closure designed to 'form a pressure-sustaining impregnation chamber, means including a valve for supplying an impregnating liquid above atmospheric pressure to said chamber, means operable automatically to open said valve, hydraulic means arranged to produce successive stages oi minus pressure and plus pressure of the liquid in said chamber, and means responsive to the rise of liquid in said chamber to initiate the operation of said bydraulic means.

32. A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, means including a valve for supplying an imrregnating liquid above atmospheric pressure to said chamber, means operable automatically to open and close said valve, means arranged to produce successive stages of minus pressure and plus pressure of the liquid in said chamber, means operable automatically to retract said closure from the receptacle, and automatic con-. 76 trolling means arranged to initiate the opera'-' tion or said retracting means at the conclusion =of a series of said minus and plus pressure stages. I

33. A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, means for supplying an impregnating liquid above atmospheric pressure to said chamber, a timing device, automatic means'controlled by said timing device to retract said closure at the conclusion of a measured period of time, and

which said hydraulic means is controlled to retract said closure at the conclusion of a measured time interval, means controlled by said hydraulic means to supply an impregnating liquid above atmospheric pressureto said impregnating chamber, and means controlled by said timing device to produce successive stages of minus pressure and plus pressure of the liquid in said chamber during said time interval.

35; A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, a source of impregnating liquid above atmospheric pressure, hydraulic means operable by liquid from said source to move said closure to and from the mouth of said receptacle, automatic controlling means including a timing device to supply liquid from said source to said hydraulic means for retracting said closure at the conclusion of a measured time interval, means for supplying liquid from said source to said impregnation chamber, and means controlled by said timing device during saidttime interval to produce successive stages of minus pressure and plus pressure of the liquid in said chamber.

36. A hydrauliclapparatus comprising a receptacle 'and a removable closure designed to form a pressure-sustaining impregnation chamber, means including a primary valve, a secondary valve,'and a tertiary valve, all in a series, to supply liquid above atmospheric pressure to said chamber, a double-acting hydraulic unit controlled by said primary valve for operating said closure, means operable by said hydraulic unit to open said secondary valve, automatic means arranged to close said tertiary valve and develop minus pressure of the liquid in said chamber, a timing device, and automatic means controlled by said timing device to shift said primary valve at the conclusion of a measured time interval to efiect closure-retracting operation of said hydraulic unit.

37. A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining immersion chamber, means including a primary valve, a secondary valve, and a. tertiary valve, all in a series, to supply liquid above atmospheric pressure to said chamber, hydraulic means controlled by said primary valve to operate said closure, means operable by said hydraulic means to open said secondary valve, and means controlled by the rise of liquid in said chamber to close said tertiary valve and develop minus pressure of the liquid in said chamber.

38. A hydraulic apparatus comprising, in com-- bination with the organization defined in claim 37, a timing device, and automatic means controlled by said timing device to open said tertiary valve and arrest the operation of said minus-pressure means at the conclusion of a measured time interval. 1

39. An impregnating apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamher, means arranged to fasten said closure in V chamber-closing position, means including. a valve to supply an impregnating liquid to said chamber, a timing device, means controlled by the rise of liquid imi iifld chamber to start said timing device, and means controlled by said timing device to impart successive opening and closing movements to said valve with measured time intervals between such movements.

40. A hydraulic apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, means including a pump and a distributing valve to supply an impregnating liquid to said chamber, hydraulic means controlled by, said distributing valve to retract said closure from said receptacle, an electrical circuit including a motor for operating said pump, and means operable by said hydraulic means to open said electrical circuit in consequence of retracting said closure.

41. A hydraulic apparatus comprising means forming a pressure-sustaining impregnation -chamber and including a receptacle and a removable closure therefor, hydraulic means including a pump and a double-acting ram arranged to move said closure to and from the mouth of said receptacle, an electrical circuit including the motor for operating said pump, coupled means arranged to close said circuit and supply liquid from said pump to impart closing movement to said ram, means operable by said ram to supply liquid from said pump to said impregnation chamber, a regulatable timing device, means controlled by said timing device to arrestthe supply of liquid to said chamber and supply liquid from said pump to the retracting side of said ram at the conclusion of a regulated time interval, and means operable by said ram to open said circuit when the closure is retracted.

42.A hydraulic apparatus comprising a receptacle forming a work-receiving chamber, a

work-carrier movable to and fro-to carry work into and out of said chamber, means including a pump to supply liquid to treat the work supported in said chamber by said carrier, an 'electrical circuit including a motor for operating said pump, hydraulic means for operating said work-carrier to retract the work from said chamber, a timing device, automatic means controlled v by said timing device to supply liquid from said pump to said hydraulic means at the conclusion 5 of a measured time interval, and means operable by retractory movement of said hydraulic means to open said electrical circuit.

43. A hydraulic apparatus comprising a receptacle forming a work-receiving chamber, a workcarrier movable to and fro to carry work into and out of said chamber, hydraulic means arranged to retract said carrier from said receptacle, means including a pump and a distributing valve to supply liquid alternatively to said chamber and said hydraulic means, an electrical circuit including a motor for operating said pump, means operable by said valve to close said circuit when the valve is operated to supply liquid to said chamber, and means operable by said hydraulic means to open said circuit when the workcarrier is retracted.

44. In a hydraulic apparatus of the type in which a locking member is carried by a closure to secure the latter to a receptacle in which work is to be impregnated and into which an impregnating liquid is to be admitted at plus pressure from a source of supply; the combination comprising an initially closed valve for controlling the admission of the liquid into said receptacle, and operating means by which locking movement of said locking member causes opening movement of said valve.

45. An impregnating apparatus comprising a receptacle and a removable closure designed to form a pressure-sustaining impregnation chamber, means arranged to fasten said closure in chamber-closing position, means including two individually operable valves in a series to supply an impregnating liquid to said chamber, one of said valves being arranged to be opened by said fastening means, a timing device, means controlled by the rise of liquid in said chamber to close the other one of said valves, start said timing device and thereafter reopen the valve so closed, the reopening operation of said means being controlled by said timing device to .take effect at the conclusion of a measured time interval.

46. An impregnating apparatus comprising a receptacle and a removable closure designedjto form a pressure-sustaining impregnation chamber, means arranged to fasten said closure in chamber-closing position, means including two individually operable valves in a series to supply an impregnating liquid to said chamber, one of said valves. being arranged to be opened by said fastening means, and means controlled by the rise of liquid in said chamber for closing the other one of said valves.

4'7. A hydraulic apparatus comprising a receptacle and aremovable closure designed to form a work-treating chamber, a hydraulic unit arranged to operate said closure, a guard movable to and from an operative position with respect to said receptacle, a hydraulic unit arranged to operate said guard, means for supplying an operating liquid to said units, a valve arranged to control the supply of liquid to said units, and automatic means arranged to operate said valves.

48. A hydraulic apparatus comprising a reciprocatory member and' a reciprocatory guard therefor, hydraulic cylinders having individually movable pistons by which said member and said guard may be operated respectivels, and means including a valve and distributing conduits for supplying operating liquid above -atmospheric presure to opposite ends alternately of said pistons.

49. An apparatus as defined in claim 48 in which the elements are organized to complete the strokes of said guard earlier than the corresponding strokes of said member.

GEORGE PICKFORD. BERNARD S. LEE. 

